Search inside publication
Iron-bearing groundwater makes phosphate less harmfull
The release of phosphorus (P) to surface water from heavily fertilised agricultural fields is of major importance for surface water quality. New PhD research financed by Deltares showed that the effects of phosphate losses from agricultural sources on the ecological quality of surface water are smaller than previously thought. The conclusion was that Netherlands is fortunate that the water system in many places immobilises large amounts of dissolved phosphorus and stores it in ditches.
The Dutch Delta Approach
Deltares is engaged in several projects where adaptive delta management is being transferred and adapted to other delta countries as a policy model. This project aims to understand why the process of policy transfer is so challenging and it is exploring how these challenges can be addressed.
Cascading effects of infrastructure disruption and identification of vulnerable groups
The CIrcle-Bao tool was used to incorporate local knowledge and experiences in the analysis of the cascading effects of critical infrastructure failure or disruption due to flooding in the Manzese ward, Dar es Salaam (Tanzania). CIrcle-Bao is an offline equivalent of the CIrcle webtool.
Energy production with floating solar farms
Sustainable energy production is booming business and more and more initiatives are being planned for floating solar panel farms. Clear legislation is required for both permit authorities and the organisations planning the farms. New tools provide an insight into all the legislative considerations, as well as the potential impact on water quality and ecology of the water bodies in question.
Visual communication in science and landscape design
During a four-year PhD project, WUR and Deltares developed a new framework to analyse visual representations as a means of communication in spatial planning and design projects. The framework serves as a basis for a visualisation strategy that allows Deltares to communicate our expertise more effectively during participatory processes relating to climate adaptation.
Increasing the resilience of maritime transport in Tuvalu
People from Niutao and Nanumanga, two of the outer islands of Tuvalu, rely heavily on shipping to supply life’s necessities but also to prepare and respond to a crisis or emergency. New maritime infrastructures are expected to improve the living standards of the local population and the resilience of Tuvalu’s maritime sector. A study was carried out that forms the basis for the development of new ship landing facilities on the islands.
Experiment-supported modelling of salt marsh establishment
Recently, the use of salt marshes in front of hard structures is increasingly proposed as a more sustainable coastal protection measure. Yet, salt marsh restoration and creation is often hampered by the lack of a thorough understanding of initial vegetation establishment. Recent studies highlight the importance of bed level change for salt marsh development. In this study we continue the examination of the impact of bed level change on salt marsh development, focussing on the prediction of salt marsh establishment and the implications for coastal management. First, a test with Spartina anglica seedlings (Cordgrass) in a wave flume showed that long-term (seasonal) bed level change is more important for seedling survival than direct wave impact at the shoot. Therefore, we subsequently incorporated bed level change in the Windows of Opportunity (WoO) framework. Lastly, this revised WoO framework was applied to the design of the Marconi pioneer salt marsh (The Netherlands). Combining the WoO framework with a morphodynamic model (Delft3D) showed its potential for salt marsh design. The framework can be used to determine whether salt marsh establishment is possible, to find out which conditions are limiting establishment and to design engineering measures creating the conditions that facilitate salt marsh establishment.
Bivalve aquaculture carrying capacity : concepts and assessment tools
The carrying capacity concept for bivalve aquaculture is used to assess production potential of culture areas, and to address possible effects of the culture for the environment and for other users. Production potential is depending on physical and production carrying capacity of the ecosystem, while ecological and social carrying capacity determine to what extent the production capacity can be realized. According to current definitions, the ecological carrying capacity is the stocking or farm density of the exploited population above which unacceptable environmental impacts become apparent, and the social capacity is the level of farm development above which unacceptable social impacts are manifested. It can be disputed to what extent social and ecological capacities differ, as unacceptable impacts are social constructs. In the approach of carrying capacity, focus is often on avoiding adverse impacts of bivalve aquaculture. However, bivalve populations also have positive impacts on the ecosystem, such as stimulation of primary production through filtration and nutrient regeneration. These ecosystem services deserve more attention in proper estimation of carrying capacity and therefore we focus on both positive and negative feedbacks by the bivalves on the ecosystem. We review tools that are available to quantify carrying capacity. This varies from simple indices to complex models. We present case studies of the use of clearance and grazing ratio’s as simple carrying capacity indices. Applications depend on specific management questions in the respective areas, the availability of data and the type of decisions that need to be made. For making decisions on bivalve aquaculture, standards, threshold values or levels of acceptable change (LAC) are used. The FAO framework for aquaculture is formulated as The Ecosystem Approach to Aquaculture. It implies stakeholder involvement, and a carrying capacity management where commercial stocks attribute in a balanced way to production, ecological and social goals. Simulation models are being developed as tools to predict the integrated effect of various levels of bivalve aquaculture for specific management goals, such as improved ecosystem resilience. In practice, bivalve aquaculture management is confronted with different competing stocks of cultured, wild, restoration and invasive origin. Scenario models have been reviewed that are used for finding the balance between maximizing production capacity and optimizing ecological carrying capacity in areas with bivalve aquaculture.
Erosion of sandy beaches worldwide
A unique, high-resolution dataset has been developed showing decade-scale shoreline trends using freely available satellite images. This allows for the worldwide analysis and quantification of coastal erosion and accretion, and it may provide an understanding of the effects of climate change on coastal erosion.
Detecting trends in climate change
Adaptive planning is a new paradigm in policy making to deal with deep uncertainties. Key to the method is the early detection of changes that require mitigation. In this study, we explored the benefits of combining information from multiple rivers to obtain earlier and/or more reliable signals of climate change.